Abstract: Scanned, colored and gray-scale documents are compressed. The digital image of the scanned document is divided into three image planes. These image planes are a foreground image, a background image and a binary mask image. The mask image describes which areas of the document belong to the foreground and which to the background. Components of the foreground are text and graphic elements. The color and intensity of these foreground areas is described by the foreground image. The background areas include the text background as well as the pictures contained in the document. The color or brightness information of the background as well as the images contained in the document are contained in the background image. Each of the three images is coded separately with a suitable image coding method. For the decoding, the document is assembled once again from the foreground and background images.

Abstract: The invention can be used in a wide range of fields including space applications, for observing, measuring and surveying the earth surface with satellites, civilian and military aeronautics, for x-ray images and security applications, as well as in general industrial image processing and image generation applications. The invention uses the advantages of the wavelet transformation, a mathematical mapping between spaces, and in particular the advantages of interpolating wavelets, to improve the transmission of endless, continually growing, non-bordered images using a small amount of memory. The invented procedure and the proposed implementation of the procedure describe a complete wavelet transformation system which is used as a decorrelating transformation for digital or digitized input data. The invention also covers an inverse wavelet transformation system for reverting the wavelet transformation system operations.